This invention has been devised to improve U.S.L.P. No. 4,848,699, which has been found to have the drawbacks in its mechanical structure listed below.
1. The gear disc 32 engages the shaft of the motor at a 90.degree. angle for transmitting power along a point and a face so that the gear disc 32 may become loose and unstable, emitting comparatively large noise with resultant inferior stability in power transmission.
2. The gear disc 32 easily becomes so loose that tape rewinding or starting cannot be performed as expected.
3. The service life may be shortened because of the quick wear and tear of the parts caused by unstable performance in the power transimission.